ok i'm not sure if anyone has had this same problem but, I just put some 18x7.5's on my car and I have noticed alot of noise um like a humming I compare it to a truck with mudders going down the road type noise, the faster I go the louder it gets. Has anyone had this same noise after going to a larger rim tire combo? will a alignment help? or like i have read in other threads is it a suspension issue?:

 

new tire breaking in period?
some tire types chosen on tirerack will warn you of a harsher ride when you click buy
overinflation?

 

With a more aggressive tread pattern, ala high performance tires, you will get more noise like that hum, which will increase with speed. Also, if the tires are a lower profile, the hum is often heard.